Troubleshoot Lumia when It Doesn't Work for You

Try these fixes if, for example, your phone randomly reboots, freezes or does not switch on, if an app crashes, if you have sound problems, or if the screen is blank:

Charge your phone. Charge your phone for at least 20 minutes.

Restart your phone. Press and hold the Power and Volume down keys simultaneously for 10-15 seconds. Release and the phone will restart. After this operation, you may need to set the date and time on the phone. If the problem persists, reset and restore your phone as instructed below.

Reset your phone.

NOTE: This erases all personal content on your phone and restores the factory settings.

Before continuing with the reset, make sure your phone's battery level is above 50%. To check the remaining battery life, go to Settings > System > Battery saver (Lumia with Windows Phone 8: Settings > battery saver). If you are not able to check it, or the level is too low, charge your phone for at least 20 minutes.

What f you cannot access the phone settings

Please follow the steps below:

1

Disconnect the charger

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Press and hold the Power and Volume down keys simultaneously. Release the keys when the phone vibrates and then immediately press and hold the volume down key until the phone displays an exclamation mark (!) on the screen. Release the volume down key.